A new study explains why humans don't have tails. It shines a bewildering light on the role of chance in the evolutionary trajectory of how we became ourselves—and why "good enough" often works.
I see Klaas is again in session. Lovely to awaken to. Thanks, Brian. Cup of coffee and this essay, day is off to a good start. We lack tails, but not an excess of Tales—most of them dubious. 🤣
Well put! It’s funny because every single post about when to send emails to people says to avoid weekends like the plague and focus on Tuesday/Wednesday/Thursday but personally I’m more likely to read something like this with a cup of coffee on a weekend, so I figure some others might be the same. Glad I was right in your case!
My sentiments exactly. Actually awoke, arisen, got my weekend brew of Yemen coffee, and tucked up with “Tails”. Good way to start a rainy Sunday. And I always gently stroke my Luna’s long skinny tail multiple times with the mantra “Such a beau-u-u-u-tiful tail!” And she wriggles her butt and rolls her eyes in delight! Thank you for the enlightenment!
I enjoyed the essay and I completely agree that popular misinterpretations of evolutionary theories have done (and continue to do) much societal harm. That evolution is not strictly adaptive has long been known to evolutionary biologists, and it is good to make that knowledge available outside the specialized field. However, science marches on and a recent study indicates that evolution may not be so random after all (https://www.sciencedaily.com/releases/2024/01/240108125801.htm). It turns out that there may be predictability in non adaptive evolution because of interactions with other genes that in a sense 'determine' which mutations stick. The famed popularizer of evolution Stephen Jay Gould wrote that if we replayed the tape of evolution over and over again, it would lead to different results. That may be too simple and replaying the tape may actually lead to the same or similar results. It makes intuitive sense to me. It is difficult to imagine that the integrity of very complex systems could be maintained under purely random processes. This is not the same as optimization so the gist of your argument stands. All it would mean is that random mutations land in pre-existing ecosystem of genes which constrains what happens next.
Yeah, there’s a chapter in Fluke all about this - and I basically believe in what I call contingent convergence. Some stuff follows structured patterns, but every so often, a random diverting of the evolutionary trajectory happens that sticks. Also, we don’t know what the endpoint of convergence is…in other words, let’s imagine that a trait will get eliminated by evolutionary forces over 10 million years. We don’t know a) how long it will take; or b) how far along that pathway “we” are. We could be 2 million years along the road, or 9.9, and we wouldn’t know the difference. So it’s a huge error to assume that a) everything will get culled if it’s not adaptive; and more egregiously that b) everything around us already has been culled, therefore everything around us must have some purpose and be adaptive. Those fallacies both still exist in evolutionary biology and I think Milo does a good job of taking them on, even if I don’t agree with everything he says or his overly uniform depiction of evolutionary biology as a field.
Good explanation of timelines, and arbitrariness, Brian.
Mankind now has 'less body hair than when we started'.
So, probably we have less than humans did in the 1500's; they had less than humans did 42K years ago. Probably.
We've kept some body hair- more prominently the arm pits, and pubic area-why? Will we lose it all in 250 years? 2000 years? 2 million?Why or why not?
Once we accept that there is order in the universe, we cajole ourselves to (sentimentally) conclude that that order is complete and absolute, and determinable by us.
Hee Hee. I can think of an adaptationist reason for separation of apes from monkeys. Mutation first appears in a new area of short trees. It spreads because falling out of a short tree is no big deal. Trees grow. Pretty soon, the SMART tailless ones figure out it's better on the ground. The others bash their heads as they slip trying to follow mommy in the treetops.
Bingo. explains both apes without tails AND why they developed into smarter species.
But looking around at the world today, one has to wonder about smartness. So I'll go with your interpretation.
Many good points about the adaptation error in pop evolution. Of course, the example of birds being the only dinosaurs to survive made this point a few decades ago. Why birds? Anyone? Bueler?
Also, my definition of luck: Luck is the intersection of where preparation meets opportunity. But nobody knows when, where, or if opportunity ever comes! And one does not know if your preparation is what matches the opportunities that do present themselves.
Life and the pace of events are a stochastic process, though we have no clue how that process works. Randomness just means there is no predictable pattern in many things, be it evolutionary biology or the next big geo-political event. As we used to say in grad school, “Measure zero events occur everyday.”
But what is interesting this exposition is how we as humans, arrogant and self-important as we are, must find patterns and meanings. The idea of survival of the fittest and “social Darwinism” was just an offshoot of religious ideas of being chosen by God for being King, Queen, or why some groups and families had status while others did not. It is basically an excuse for random chance accompanied by brutal and savage actions that led to the rise of families to control land and people. It makes those that made it sound “better and more entitled” than others and using religion or “science” to justify their positions and remaining there.
While we kind find patterns and some predictability, they are not steadfast nor immune to serious disruptions coming from outside that contained system. And there is no way to predict or understand what those disruptions will be and how they will affect a system. That is the random component and that is what makes life so interesting and why I have a job. If we could model everything we would just go home and be done!
I see Klaas is again in session. Lovely to awaken to. Thanks, Brian. Cup of coffee and this essay, day is off to a good start. We lack tails, but not an excess of Tales—most of them dubious. 🤣
Well put! It’s funny because every single post about when to send emails to people says to avoid weekends like the plague and focus on Tuesday/Wednesday/Thursday but personally I’m more likely to read something like this with a cup of coffee on a weekend, so I figure some others might be the same. Glad I was right in your case!
Yeah. I find it interesting that I consistently get a LOT my traffic spikes on my lttle pissant ankle-biter blog on the weekends. Go figure.
I keep thinking about that very small group of tailless apes. And that one shrew. Change come fast and change come slow, but change come.
I was fascinated by the movie "Avatar" in part because that futuristic society had tails. Blue "folks" with tails!
See also Katayans in Mary Gentle's "Rats and Gargoyles" (and, come to think of it, Vegians in Doc Smith's "Masters of the Vortex" 🙂)
Still want one; wish I had one. One tiny genetic tweak… »sigh«
My sentiments exactly. Actually awoke, arisen, got my weekend brew of Yemen coffee, and tucked up with “Tails”. Good way to start a rainy Sunday. And I always gently stroke my Luna’s long skinny tail multiple times with the mantra “Such a beau-u-u-u-tiful tail!” And she wriggles her butt and rolls her eyes in delight! Thank you for the enlightenment!
I enjoyed the essay and I completely agree that popular misinterpretations of evolutionary theories have done (and continue to do) much societal harm. That evolution is not strictly adaptive has long been known to evolutionary biologists, and it is good to make that knowledge available outside the specialized field. However, science marches on and a recent study indicates that evolution may not be so random after all (https://www.sciencedaily.com/releases/2024/01/240108125801.htm). It turns out that there may be predictability in non adaptive evolution because of interactions with other genes that in a sense 'determine' which mutations stick. The famed popularizer of evolution Stephen Jay Gould wrote that if we replayed the tape of evolution over and over again, it would lead to different results. That may be too simple and replaying the tape may actually lead to the same or similar results. It makes intuitive sense to me. It is difficult to imagine that the integrity of very complex systems could be maintained under purely random processes. This is not the same as optimization so the gist of your argument stands. All it would mean is that random mutations land in pre-existing ecosystem of genes which constrains what happens next.
Yeah, there’s a chapter in Fluke all about this - and I basically believe in what I call contingent convergence. Some stuff follows structured patterns, but every so often, a random diverting of the evolutionary trajectory happens that sticks. Also, we don’t know what the endpoint of convergence is…in other words, let’s imagine that a trait will get eliminated by evolutionary forces over 10 million years. We don’t know a) how long it will take; or b) how far along that pathway “we” are. We could be 2 million years along the road, or 9.9, and we wouldn’t know the difference. So it’s a huge error to assume that a) everything will get culled if it’s not adaptive; and more egregiously that b) everything around us already has been culled, therefore everything around us must have some purpose and be adaptive. Those fallacies both still exist in evolutionary biology and I think Milo does a good job of taking them on, even if I don’t agree with everything he says or his overly uniform depiction of evolutionary biology as a field.
Good explanation of timelines, and arbitrariness, Brian.
Mankind now has 'less body hair than when we started'.
So, probably we have less than humans did in the 1500's; they had less than humans did 42K years ago. Probably.
We've kept some body hair- more prominently the arm pits, and pubic area-why? Will we lose it all in 250 years? 2000 years? 2 million?Why or why not?
Once we accept that there is order in the universe, we cajole ourselves to (sentimentally) conclude that that order is complete and absolute, and determinable by us.
We keep being proven wrong. We keep believing.
Hee Hee. I can think of an adaptationist reason for separation of apes from monkeys. Mutation first appears in a new area of short trees. It spreads because falling out of a short tree is no big deal. Trees grow. Pretty soon, the SMART tailless ones figure out it's better on the ground. The others bash their heads as they slip trying to follow mommy in the treetops.
Bingo. explains both apes without tails AND why they developed into smarter species.
But looking around at the world today, one has to wonder about smartness. So I'll go with your interpretation.
“looking around at the world today, one has to wonder about smartness.” — Ding, ding, ding, We Have a Winner. 🤣🍷
I admire you for not once mentioning ‘Intelligent Design.'
Many good points about the adaptation error in pop evolution. Of course, the example of birds being the only dinosaurs to survive made this point a few decades ago. Why birds? Anyone? Bueler?
Also, my definition of luck: Luck is the intersection of where preparation meets opportunity. But nobody knows when, where, or if opportunity ever comes! And one does not know if your preparation is what matches the opportunities that do present themselves.
Life and the pace of events are a stochastic process, though we have no clue how that process works. Randomness just means there is no predictable pattern in many things, be it evolutionary biology or the next big geo-political event. As we used to say in grad school, “Measure zero events occur everyday.”
But what is interesting this exposition is how we as humans, arrogant and self-important as we are, must find patterns and meanings. The idea of survival of the fittest and “social Darwinism” was just an offshoot of religious ideas of being chosen by God for being King, Queen, or why some groups and families had status while others did not. It is basically an excuse for random chance accompanied by brutal and savage actions that led to the rise of families to control land and people. It makes those that made it sound “better and more entitled” than others and using religion or “science” to justify their positions and remaining there.
While we kind find patterns and some predictability, they are not steadfast nor immune to serious disruptions coming from outside that contained system. And there is no way to predict or understand what those disruptions will be and how they will affect a system. That is the random component and that is what makes life so interesting and why I have a job. If we could model everything we would just go home and be done!